This application is based on Japanese Patent Application No. 9-361461 (1997) filed Dec. 26, 1997 and Japanese Patent Application No. 10-364571 (1998) filed Dec. 22, 1998, the contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a method for forming an image and an apparatus for forming the same, and particularly to fixing technology in a case of forming an image by using ink and a processing solution to insolubilize the ink.
2. Description of the Related Art
In ink-jet printing technology for performing printing by using a solution such as the ink of the present invention, etc., fixation of the ink after printing is one of important subjects. If the fixation is poor, there is a fear of inconvenience in handling printed matters outputted from a printer or a fear of staining other printed matters when they are arranged to be laminated for being put into storage.
As a means for improving such fixing, an accelerator to evaporate solvent such as water content in the ink, etc. by using a heating means such as a heater or the like is known. The use of such a heating means permits an across-the-board or better improvement in fixation of ink with any penetration speed from a high penetrability to a low penetrability.
However, in an arrangement of using a heater, a total power consumption of a printer becomes relatively high. Especially, when a higher speed printing is desired, a the shorter time is required for fixing and more heat has to be supplied, and this results in an especially large power consumption. Further, heating by heater is performed on the printing medium during feeding or conveyance, but if the heater is arranged along the conveyance path, a printer is upsized more and this is not always a suitable arrangement from a down-sizing point of view for the equipment.
As opposed to this, it is also known that an ink with a high penetrability is used and fixation of the ink itself is thereby improved.
The object of the present invention is to solve at least one of the following problems. Namely, they are:
to provide a new image-forming technology,
to improve fixation without using a means such as a heater, etc. even when an ink with a slow penetrability is used, and
to rapidly fix an ink containing a color material such as black, etc. while achieving a high optical density.
In a first aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by using each of different plural droplets,
wherein a concentration of a surface-active agent in a droplet, into which the different plural droplets for constituting the image to be formed have coalesced on a printing medium surface, is the critical micell concentration of the surface-active agent in pure water or higher.
Here, a concentration of a surface-active agent in at least one of the different plural droplets may be less than the critical micell concentration of the surface-active agent in pure water, and a concentration of a surface-active agent in at least one of another droplets may be the critical micell concentration of the surface-active agent in pure water or higher.
The surface-active agents may be ethylene oxide-2, 4, 7, 9-tetramethyl-5-decine-4, and 7-diol, and droplets, in which concentrations of the surface-active agents are the critical micell concentrations of the surface-active agents in pure water or higher, may have contents of 0.7% or higher in the droplets corresponding to the surface-active agents.
In a second aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by using each of different plural droplets,
wherein a surface tension of a droplet, into which the different plural droplets for constituting the image to be formed have coalesced on a printing medium surface, is less than 35 dyne.
Here, the surface tension of at least one of the different plural droplets may be less than 35 dyne, and the surface tension of at least one of another droplets may be not less than 35 dyne.
In a third aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by using each of different plural droplets,
wherein Ka value of penetration speed of a droplet, into which the different plural droplets for constituting the image to be formed have coalesced on a printing medium surface, is not less than 5 [ml/m2xc2x7mscxc2xd].
Here, Ka value of at least one of the different plural droplets may not be less than 5 [ml/m2xc2x7msecxc2xd], and Ka value of at least one of another droplets may be less than 5 [ml/m2xc2x7msecxc2xd].
In any of the above aspects of the present invention, each of the different plural droplets may be an ink droplet containing color material.
The different plural droplets may contain processing solution droplets to insolubilize the color materials in the ink droplets and addition of the processing solution droplets onto printing medium may be performed later than at least one of the ink droplets.
The ink droplets may contain ink droplets mainly having dyes as color materials.
The ink droplets may contain ink droplets mainly having pigments as color materials.
The ink droplets may contain ink droplets mainly having dyes as color materials and ink droplets mainly having pigments as color materials.
The ink droplets mainly having pigments may contain dispersing agent for dispersing the pigments.
The ink droplets mainly having pigments may contain self-dispersing type pigments.
In a fourth aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by adding at least one of the ink droplets before adding processing solution droplets to insolubilize color materials in the ink droplet.
wherein a concentration of a surface-active agent in a droplet, into which at least one of the ink droplets and the processing solution droplets have coalesced on a surface of a printing medium constituting an image to be formed, is not less than the critical micell concentration of the surface-active agent in pure water.
In a fifth aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by adding at least one of the ink droplets before adding processing solution droplets to insolubilize color materials in the ink droplet,
wherein a surface tension of the droplet, into which at least on the one of ink droplets and the processing solution have coalesced on a surface of a printing have coalesced on a surface of a printing medium constituting an image to be formed, is less than 35 dyne.
In a sixth aspect of the present invention there is provided a method for forming an image comprising the step of:
forming an image by adding at least one ink droplet before adding processing solution droplets to insolubilize color materials in the ink droplet,
wherein Ka value indicating a penetration speed of the droplet, into which at least the one ink droplet and the processing solution have coalesced on a surface of a printing medium constituting an image to be formed, is not less than 5[ml/m2xc2x7msecxc2xd].
In a seventh aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by adding at least one ink droplet before adding processing solution droplet to insolubilize color materials in the ink droplets and then, further adding at least another ink droplet,
wherein a concentration of a surface-active agent in the droplet, into which at least the one ink droplet and the processing solution have coalesced on a surface of a printing medium constituting an image to be formed, is not less than the critical micell concentration of the surface-active agent in pure water.
In an eighth aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by adding at least one ink droplets before adding processing solution droplets to insolubilize color materials in the ink droplet and then, further adding at least another ink droplet,
wherein a surface tension of the droplet, into which at least the one ink droplet and the processing solution have coalesced on a surface of a printing medium constituting an image to be formed, is less than 35 dyne.
In a ninth aspect of the present invention, there is provided a method for forming an image comprising the step of:
forming an image by adding at least one ink droplets before adding processing solution droplets to insolubilize color materials in the ink droplet and then, further adding at least another ink droplet,
wherein Ka value indicating a penetration speed of the droplet, into which at least the one ink droplet and the processing solution have coalesced on a surface of a printing medium constituting an image to be formed, is not less than 5[ml/m2xc2x7msecxc2xd].
In a tenth aspect of the present invention there is provided an image forming apparatus comprising:
means for forming an image by using discharging portions for discharging each of different plural droplets and discharging the droplets onto a printing medium from the discharging portions,
wherein the concentration of the surface-active agent in the droplet, into which the different plural droplets have coalesced on a surface of a printing medium constituting an image to be formed, becomes not less than the critical micell concentration of the surface-active agent to pure water.
In an eleventh aspect of the present invention, there is provided an image forming apparatus comprising:
means for forming an image by using discharging portions for discharging each of different plural droplets and discharging the droplets onto a printing medium from the discharging portions,
wherein the surface tension of the droplet, into which the different plural droplets have coalesced on a surface of a printing medium constituting an image to be formed, is less than 35 dyne.
In a twelfth aspect of the present invention, there is provided an image forming apparatus comprising:
means for forming an image an image by using discharging portions for discharging each of different plural droplets and discharging the droplets onto a printing medium from the discharging portions,
wherein Ka value indicating a penetration speed of the droplet, into which the different plural droplets have coalesced on a surface of a printing medium constituting an image to be formed, is not less than 5[ml/m2xc2x7msecxc2xd].
According to the above arrangement, a critical micell concentration, a surface tension, and Ka value, which represent a penetrability of a droplet of different plural droplets such as those of ink, processing solution, etc. joined with a printing medium, have predetermined values or higher of a penetrability, therefore, even if some of the individual droplets have a low penetrability, the penetration of the joined droplets is accelerated.
Thus, even if ink of a low penetrability is used for improving optical density value (OD value) or suppressing feathering, a high penetrability is shown for the combined droplets and the fixation is not inhibited.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.